The present disclosure relates to an electric power receiving apparatus, a method of controlling the same, and an electric power feeding system including the same. More particularly, the present disclosure relates to an electric power receiving apparatus in a non-contact type electric power feeding system which electrically feeds an electric power in a non-contact manner, a method of controlling the same, and the non-contact type electric power feeding system including the same.
Heretofore, a circuit for detecting an object which enters a magnetic field generated between an electric power feeding apparatus and an electric power receiving apparatus in the form of a foreign object is provided in a non-contact type electric power feeding system for electrically feeding an electric power in a non-contact manner in some cases. The reason why such a circuit is provided is because when the foreign object composed of an electric conductor enters the magnetic field, an eddy current is generated within the foreign object, and the foreign object generates heat by an influence of the Joule heat due to the eddy current in some cases. When an amount of heat generation of the foreign object is large, it is feared that an apparatus and a chassis in the non-contact type electric power feeding system are damaged. In particular, since in quick charging, the strength of the magnetic field outputted by the electric power feeding apparatus become large, an amount of heat generation of the foreign object becomes large, and thus the presence of the foreign object becomes a problem in many cases.
A circuit for determining presence or absence of a foreign object depending on whether or not amplitude of a voltage induced on an electric power receiving side is smaller than a reference value, for example, is proposed as a circuit for detecting a foreign object. This circuit, for example, is described in Japanese Patent Laid-Open No. 2012-16125. With this circuit, when the foreign object is present, a loss in the electric power is generated due to the eddy current generated in the foreign object and thus an electric power feeding efficiency is reduced. Therefore, the foreign object is determined to be present when the amplitude of the voltage on the electric power receiving side is reduced so as to be smaller than the reference value.